Who is Twet Nga Lu from The Piano Tuner and what is their importance?

Twet Nga Lu is an infamous bandit in the Shan States. He attacks towns and villages, as well as travelers. Everyone fears him, and the land is not safe until he is subdued. He began his banditry when the local sawbwas left their thrones empty to form the Limbin Confederacy. He moved in, seizing the throne of Mongnai. The Limbin Princes have since repelled the bandits and Twet Nga Lu has fled back to his local village, but he continues to pray on the Shan villages and people. There are a lot of stories about Twet Nga Lu, particularly concerning his many fearsome tattoos.